Preliminary assessment of use of spider webs for the indication of air ...

Environment Protection Engineering
Vol. 38 2012 No. 3
DOI: 10.5277/EPE120315
JUSTYNA RYBAK*, IZABELA SÓWKA*, ANNA ZWOŹDZIAK*
PRELIMINARY ASSESSMENT OF USE OF SPIDER WEBS
FOR THE INDICATION OF AIR CONTAMINANTS
Spider webs found in polluted areas could absorb air contaminants. In order to check their cumulative
ability, two different study sites had been chosen in Wrocław (in the area of wet ponds and
in the residential district of Biskupin) where spider silk was collected (after 10 days from the time of
its construction). Web types of appropriate thickness and size were chosen for analyses. The representatives
of Agelenidae family belonging to two species Malthonica silvestris and Malthonica ferruginea
proved to be the most adequate for further studies. The level of selected heavy metal cumulation
was assessed (Pb, Zn, Pt) in the collected samples. As the background, the level of air pollution
concerning dust and selected heavy metals was also analysed by classic methods. Based on the web
analysis, it was found that site 2 (Biskupin) exhibited the highest level of pollution with some metals.
Similar results were obtained with the application of classic methods. The results of research are
promising and confirm the possibility of obtaining a practical tool for the indication of air pollutants
based on spiders silk, particularly on webs belonging to Agelenidae family.
1. INTRODUCTION
Combustion gases are much more harmful to people than pollutants deriving from
the industry, because they spread in higher concentrations, on lower heights in the
direct vicinity of people [1–3]. Air pollution causes annually about 6% of all recorded
fatal cases [4]. The pollution coming from transport is responsible for half of them.
The research conducted in tunnels, multi-storey car parks, under the bridges and in
surroundings of petrol stations showed from 4 to 40 times higher concentration of
pollutants than in the entire urban areas. It was estimated that 15 mln of hectares of
Poland, almost half of the territory of our country, remains directly under the influence
of emission coming from the motorization [3, 5]. In the city, the total concentration of
carcinogens in air is about fivefold higher than outside the city [6]. The engine combustion
gases contain a lot of carcinogens causing, in a long-term exposition, devel-
________________________
*Wrocław University of Technology, Institute of Environment Protection Engineering,
Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; corresponding author J. Rybak, e-mail:
justyna.rybak@pwr.wroc.pl

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opment of cancer cells. The most dangerous are benzene, polycyclic aromatic hydrocarbons
(PAH), dust and heavy metals. Dust is a serious threat. Coal particles have
very high absorption capacity and therefore diverse toxic substances settle easily on
their surface, including carcinogenic hydrocarbons and heavy metals [7]. Dust participates
in transporting them inside the human body. It irritates eyes, skin and respiratory
tract (pneumoconiosis). Diesel engines are main source of dust emission [8].
As spider webs absorb air pollution from the environment, they can be useful indicators
of air quality. The advantages of application of spider webs are as follows: low
cost of samples collection, availability of the research material, secluded location preventing
their destruction by weather conditions (falls, wind, snow) and people, noninvasiveness
of studies (no need of killing animals), easy collection of samples. Moreover,
studies conducted so far [9] show that cumulative ability of webs is an additional
advantage. Such ability, being a consequence of its chemical structure, gives an unique
opportunity to asses an air pollution level in a long-term period, contrary to the classic
measurements which could only deliver information about the temporary state of the
environment. Additionally, measurement of concentrations of pollutants is usually carried
out with expensive and inconvenient equipment (large-sized and noisy apparatus).
On the opposite, webs collection from tunnel walls is fast and enables one to study
a long-term influence of pollutants only by single examinations (e.g. 7 or 30 days).
Application of high-tech passive dosimeters formally discredits the legitimacy of
webs use, however it is worth to emphasize that even a relatively cheap and simple
dosimeters cannot be left in random places in case of theft or destroy. Another advantage
is that webs are usually found in large numbers, often in places where it is hard to
install the dosimeter and usually do not attract any attention. What is more, it is possible
to date the time of the web exhibition to pollutants by removing the old web and
using only a new construction.
Cumulative ability of spider webs has not been analysed in Poland. Assessment of
usefulness of webs for the indication of the environment is the aim of presented studies.
The obtained results could contribute to the development of an easy method of
pollution indication which can function almost all year round (webs can be obtained
under laboratory conditions by breeding spiders) which could be an additional advantage
of the method, unlike the majority of bioindication methods where application is
often limited only to the vegetative season (e.g. assessment of water quality based on
benthic macroinvertebrates) [10, 11].
2. EXPERIMENTAL
Webs were collected from the two following study sites within city of Wrocław.
Site 1. Hydrotechnical building on water supplying areas of Wrocław (wet ponds)
is located in the south-east part of the city. A flat area (1026 hectares) consisted of

Spider webs for the indication of air contaminants 177
meadows, only partly overgrown with bush and trees, covered with the system of
ditches and channels supplying water to 63 infiltration ponds. Drinking water is delivered
for the city of Wrocław from this area and from the river Oława, which is fed
with water from Nysa Kłodzka. The area lies distantly from the main communications
trails. Spider silk was collected from the hydrotechnical building.
Site 2. Biskupin, the housing estate which is situated in the eastern part of Wrocław,
in Śródmieście district. Odra River constitutes its natural south border. Surroundings
are diversified including areas of allotments, parks, high buildings (postwar
tenements) and low buildings (detached houses). Spider silk was collected from
fences and walls separating premises of Kosiby street.
Webs of two species: Malthonica silvestris (site 1) and Malthonica ferruginea
(site 2) have been analysed, both belonging to Agalenidae family. Malthonica silvestris
constructs triangular webs lengthening to the funnel where the spider stays all day
long (retreat). This species inhabits forests, places under stones, roots and blown down
trees. Moreover, it is possible to find M. silvestris in ruins, tunnels, as well as in caves
[12]. Malthonica ferruginea (with rust-coloured abdomen lives in forests or in surroundings
of human residences. Both species belong to the same family, weave the
similar structure (web of similar density), thus it was possible to compare the cumulative
ability of this construction in both sites.
Agelenidae family prefers dark, derelict and neglected buildings, its representatives
can also be found in tunnels and under bridges. Webs are not sticky (as webs of
many representatives of Ecribellatae suborder), consist of an opened residential tube
which widens at the front into the funnel but its lower part changes into an extensive
silk carpet with numerous signal threads, informing the spider of preys passing by.
Flies and other insects are the main prey of Agelenidae [12].
In order to check whether spider webs are able to indicate the pollution level exceeding
background values, concentrations of selected metals were defined and compared
only among webs of newly constructed and then collected in both study sites.
The dependence of webs distance from the source of emission and the influence of
webs age on the level of cumulation is the crucial matter which has already been
proved in previous studies [9]. These findings were taken into consideration in presented
analyses.
Webs of both species were collected from April to the end of May in 2009. Only
new constructions were taken into consideration. For that purpose, the area of studies
was marked and photographed in detail and all old constructions were removed. Once
a day sites were controlled in order to notify the appearance of the new webs. New
constructions were collected after each 10 days.
After the defined time the silk was gathered into clean glass phials with glass, sterile
baguettes, then webs were frozen for the future chemical analyses (the method after
Hose et al. [13]). For mineralization purpose, the samples were defrosted, dried by

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48 h at 70 °C and weighed with the accuracy of 0.0001 mg, digested in nitric acid
(70%) and warmed for drying off. Samples were suspended again in nitric acid, and
then hydrogen peroxide was added (30%). Remains were again suspended in nitric
acid and warmed to 120 ° to total digesting. Next, samples were analysed for the Pb,
Zn and Pt presence. Elements chosen for analyses are pollutants most toxic for humans.
ICP-MS, ICP-OES and AAS analyses were made in a Chemical Laboratory of
Multi-Elemental Analyses, Institute of Inorganic Technology and Mineral Fertilizers
in the Chemical Department of Wrocław University of Technology. The analytical
scheme applied at the laboratory gives the possibility of performing multi-elemental
analyses. A low detection limit enables determining concentrations of elements of
ultratrace level (with the application of the most sensitive technique ICP-MS), microelements
(ICP-OES with an ultrasonic nebuliser) and macroelements (ICP-OES with
a pneumatic nebuliser). Determining of a wide range of concentrations, with the use of
all sorts of ICP apparatuses enables a precise analysis of a delicate material such as
spider silk (the sensitivity for Pt and Pb was 0.2 ppm and for Zn 0.01 ppm).
As a background, the level of air pollution with dust PM2.5 (dust particles smaller
than 2.5 μm) was analysed on both sites by classic methods. The samples collection
performed in the period of March–May of 2009 contained twenty-four hour samples
of PM2.5 dust) within the area representing the municipal background (site 1) and
urban area (site 2). Twenty-four hour PM2.5 samples were taken with the impactor
which has been applied in the United States for a dozen years in the program of Interagency
Monitoring of Protected Visual Environment IMPROVE [14]. Dust was collected
on Teflon filters (Whatman, 2 µm PTFE 46.2 mm, air flow 22.8 dm 3 /min).
Analyses of chemical composition were performed with the fluorescence technique, of
X-ray XRF, PIXE (induced X-Ray energy proton) and PESA (proton elastic scattering
analysis) in PANalytical (Almelo, the Netherlands). The details of sampling and the
accuracy of analytical methods have been presented by Horemans et al. [15]. PESA is
usually applied in studies of hydrogen concentrations in samples. Concentrations of
22 elements have been analysed (H, S, Cl, K, Ca, Ti, Fe, Mn, Cr, V, Ni,Cu, Zn, As, Pb,
Sr, Br, Rb, Sr, Na, Al, I i Si). All data were analysed with t- test (critical value 0.05).
3. RESULTS
Both sites were significantly different (P < 0.05) concerning the concentration of
Pb, Zn and Pt in new constructions of M. silvestris and M. ferruginea. Table 1 shows
average concentrations of metals cumulated in webs for both species of spiders in two
studied areas. Figure 1 shows average concentrations of elements recorded within the
area of municipal background (site 1) and in the city centre of Wrocław (site 2). Aver-

Spider webs for the indication of air contaminants 179
age twenty-four hour Pb and Zn concentrations differed significantly (P < 0.05).
Higher concentrations were generally observed in the municipal atmosphere.
Air pollution [ng/m 3 ]
10000
1000
100
10
1
0.1
Table 1
Average concentrations of metals (± standard deviation)
in newly constructed webs of M. silvestris and M. ferruginea (sites 1 and 2)
M. silvestris
Pb
Zn
Pt
M. ferruginea
Pb
Zn
Pt
Species Site 1 Site
45±6 µg/g
201±26 µg/g
27±5 ng/g
–
–
–
4. DISCUSSION
site 1 site 2
–
–
–
85 ±4 µg/g
317±12 µg/g
67±23 ng/g
S K Ca Ti V Cr Mn Fe Ni Cu Zn As Pb Se Br Rb Sr Na Al. Si
Fig. 1. Average concentrations of elements recorded within the area
of the municipal background (site 1) and in the city centre of Wrocław (site 2)
The obtained results show a relatively high level of metals content in both sites.
Site 1, as web analysis shows, was characterised by a relatively high concentration of
Zn (water-supplying areas) compared with studies conducted by Hose et al. [13]. Such
high values are surprising; they could be result of limited, but still present car traffic in
this area or in general the high concentration of Zn in the municipal background.
Nowadays, brake pads are primary source of lead [16]. Engine oil, tyres usage are the

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basic source of pollution with zinc [17]. However, it can also originate from corrode
of building materials [18]. Differences in Zn, Pb and Pt content in webs compared
with the results achieved by Hose et al. [13] could also be connected with the age of
studied webs. A choice of spider species for studies could be also important factor
influencing results (Hose et al. [13] examined webs of species which are not recorded
in Poland), thus such comparison could only give rough values.
The emission deriving from transport decreased significantly since the introduction
of lead-free petrol, however application of catalytic converters causes the emission
of other harmful metal – platinum. Platinum is teratogenic (by damaging the foetus),
is excreted with urine leading to kidneys injuries. Small amounts of platinum
compounds are also strong allergens [3]. However, concentrations recorded in our
studies are surprisingly high, posing a great threat to people and environment. The
content of this element in spider silk has never been analysed, therefore it is not possible
to make any comparison. However, it is possible to compare the results of the
study with the concentrations recordec in dust collected in the vicinity of busy streets
of Beijing. The obtained values were from 3.96 to 356.3 ng/g, however referential
sites cumulated from 0.1 to 0.9 ng/g of Pt [18]. In our studies, site 2 achieved the
highest value (67 ng/g), site 1 was characterised by much lower value (27 ng/g) but
not as low as got referential site in Beijing.
Analyses performed with the use of classic methods show that site 2 is generally
characterised by higher level of air pollution (Fig. 1) and achieved values for Pb
23 ng/m 3 and Zn 54 ng/m 3 . However, in the area of municipal background (site 1) contents
of Pb were 13 ng/m 3 and Zn 27 ng/m 3 . When we compare the recorded concentrations
of Pb and Zn in Wroclaw with literature data it can be concluded that they fall
within the range which was obtained in the world. Average concentration of Zn in the
atmosphere of urban agglomeration of Cincinnati, USA, obtained from a few measuring
sessions, was 10–211 ng/m 3 depending on the season and location of measuring stations
[19]. The highest values were recorded in the period from August to September in the
city centre. Pb concentrations were much lower, from 3 to 28 ng/m 3 . In Vienna (Austria)
annual average values, in the municipal area, were Zn for and Pb from 22 to 17 of
ng/m 3 , however in the area located 30 km away from the city the values were lower,
appropriately 17 and 12 ng/m 3 [20]. Next, in the fast developing cities of Asia concentrations
of Zn and Pb were 245 and 79 ng/m 3 [21]. Nevertheless, it should be taken into
account that annual values are always averaged from measurements conducted within
a year and are usually lower than these recorded at short periods of time.
5. CONCLUSIONS
The aim of our studies was a preliminary assessment of the possibilities of use of
spider webs for the indication of main air pollutants. The results of the study are prom-

Spider webs for the indication of air contaminants 181
ising and confirm the working thesis that webs can serve as an effective tool for the
indication of pollutants. Webs of two Agelenidae representatives used in ours research
should be taken into account particularly because of their very good cumulative properties
deriving from high density.
ACKNOWLEDGEMENTS
The work was financed by Minister of Science and of Higher Education, research project No.
N N305 096639.
REFERENCES
[1] KONIECZYŃSKI J., PASOŃ-KONIECZYŃSKA A., Inż. Środ., 2003, 48, 89 (in Polish).
[2] ROGULA-KOZŁOWSKA W., PASTUSZKA E., TALIK E., Pol. J. Environ. Stud., 2008, 17 (4), 539.
[3] SUCHECKI B., ZOWSIK M., RYTEL K., KASSENBERG A., Effects of road transport on human health,
Zielone Mazowsze, Warszawa, 2006 (in Polish).
[4] KÜNZLI N., KAISER R., MEDINA S., STUDNICKA M., CHANEL O., FILIGER P., HERRY M., HORAK F.,
PUYBONNIEUX-TEXIER V., QUÉNEL P., SCHNEIDER J., SEETHALER R., VERGNAUD J.-C., Lancet, 2000,
35 (2), 795.
[5] ROGULA W., PASTUSZKA E, TALIK E., Arch. Ochr. Środ., 2007, 33 (2), 23 (in Polish).
[6] Bay Area Air Quality Management District, Toxic Air Contaminant Control Program, Annual Reports
for 2002, Vol. 1, June 2004.
[7] JERMANN E., HAJIMIRAGHA H., BROCKAHUS A., FREIER J., EWERS U., ROSCOVANU A., Zentralbl. Hyg.
Umweltmed., 1989, 189, 50.
[8] ZHU Y., HINDS W.C., SHEN S., KIM S., SIOUTAS C., Atmos. Environ., 2002, 36, 4323.
[9] XIAO-LI S., YU P., HOSE G.C., JIAN C., FENG-XIANG L., Bull Environ. Contam. Toxicol., 2006, 76, 271.
[10] RYBAK J., Environ. Protect. Eng., 2009, 35 (1), 111.
[11] OBOLEWSKI K., Ochr. Środ., 2009, 31 (2), 17 (in Polish).
[12] ROBERTS M.J., Spiders of Britain and Northern Europe. Collins Field Guide, Harper Collins, London,
1995.
[13] HOSE G.C., JAMES J.M., GRAY M.R., Environ. Pollut., 2002, 120, 725.
[14] AL-MASRI M.S., AL-KHARFAN K., AL-SHAMALI K., Atmos. Environ., 2006, 40, 753.
[15] HOREMANS B., WOROBIEC A., BUCZYNSKA A., VAN MEEL K., VAN GRIEKEN R., J. Environ. Monit.,
2008, 10, 867.
[16] DE MIGUEL E., LAMAS J.F., CHACON E., BERG T., LARSSEN S., ROYYET O., VADSET M., Atmos. Environ.,
1997, 31 (17), 2733.
[17] STERNBECK J., SJODIN A., ANDRÉASSON K., Atmos. Environ., 2002, 36 (30), 4735.
[18] WANG J., ZHU R., SHI Y., China J. Environ. Sci., 2007, 19, 29.
[19] MARTUZEVICIUS D., GRINSHPUN S., REPONEN T., GÓRNY R., SHUKLA R., LOCKEY J., HU S.,
MCDONALD R., BISWAS P., KLUCININKAS L., LEMASTERS G., Atmos. Environ., 2004, 38, 1091.
[20] PUXBAUM H., GOMISCEK B,, KALINA M., BAUER H., SALAM A., STOPPER S., PREINING O., HAUCK H.,
Atmos. Environ., 2004, 38, 3949.
[21] FANG G., CHANG CH., WU Y., FU P., YANG CH., CHEN CH., CHANG S., Atmos. Environ., 2002, 36,
1921.